Comparison of O-Ring Materials While selecting an O-ring for your application, a lot of importance should be placed on the material of the seal being used. Since a proper sealing action is highly dependent on the condition of your O-ring, it is important that an O-ring material be chosen to best suit the operating environment of your application. Some of the common materials used to make O-rings are nitrile rubber or Buna-N, Viton(r), silicone rubber, neoprene, and PTFE or Teflon(r).